1. Field of the Invention
This invention relates to an ion exchange method for removing contaminant metal ions from base metal electrolytic solutions.
2. Description of the Prior Art
In electrowinning and electrolytic refining operations, one is invariably confronted with the problem of build-up of contaminant metal ions in the applicable base metal electrolytic solution. For example, in the recovery of copper in either of said operations, the electrolyte will in time build up in ferric iron content. When this concentration reaches the level of about 4 grams per liter, the current efficiency is reduced to a point resulting in an unacceptably poor electroplating rate for the copper.
Hitherto, the removal of undesirable amounts of ferric iron from an electrolytic solution has been accomplished through base neutralization and metal precipitation techniques. This method of purification not only gives rise to an added cost for the base consumed, but more importantly involves difficult filtration steps so as to permit recovery of the resulting valuable metal hydroxides for recycling purposes. It is accordingly the object of this invention to provide a different expediency for removing such contaminants and specifically ferric iron from copper sulfate solutions, without encountering the disadvantages associated with the aforesaid prior art procedure.